Bottom Line:
The gene coding for TCI protein was used to construct the eukaryotic expression plasmid pcDNA-TCI.Detectable antibodies were generated in 2 weeks after immunization and their level increased after second immunization.This study demonstrates that attenuated S. enteritidis E23 is an effective live vector for rectal delivery of the DNA vaccine pcDNA-TCI to generate humoral and T-cellular responses against HIV-1.

f6: FN‐γ ELISPOT responses 35 days in the BALB/c mice twice immunized with recombinant Salmonella. , mice immunized with S. enteritidis E23/pcDNA3.1; , mice immunized with S. enteritidis E‐23/pcDNA‐TCI; , mice received physiological solution as a negative control. Mouse spleen specimens (n = 5) from each group were pooled. For all animals, the splenocytes were separately restimulated in vitro with peptide 1 (EPFRDYVDRF), peptide 2 (DRVIEVVQGAYRAIR) and peptide 3 (CTEMEKEGKISKIGP) and EHEC polypeptide as a negative control. The results are expressed as the mean numbers of IFN‐γ‐secreting cells (spots) per 5 × 105 splenocytes.

Mentions:
The T‐cell immune responses were ascertained by the presence of IFN‐γ‐producing lymphocytes detected by ELISPOT assay using peptides EPFRDYVDRF from p24, DRVIEVVQGAYRAIR from gp41 and CTEMEKEGKISKIGP from RT as HIV‐1‐specific antigens. In a murine system, these peptides are multiple class I molecules, which can be presented to CTL. Figure 6 demonstrates that immunization with S. enteritidis E23/pcDNA‐TCI triggers CTL responses in comparison with control groups. These data relate to day 35 (day 7 after the second immunization), when the immune response was the strongest.

f6: FN‐γ ELISPOT responses 35 days in the BALB/c mice twice immunized with recombinant Salmonella. , mice immunized with S. enteritidis E23/pcDNA3.1; , mice immunized with S. enteritidis E‐23/pcDNA‐TCI; , mice received physiological solution as a negative control. Mouse spleen specimens (n = 5) from each group were pooled. For all animals, the splenocytes were separately restimulated in vitro with peptide 1 (EPFRDYVDRF), peptide 2 (DRVIEVVQGAYRAIR) and peptide 3 (CTEMEKEGKISKIGP) and EHEC polypeptide as a negative control. The results are expressed as the mean numbers of IFN‐γ‐secreting cells (spots) per 5 × 105 splenocytes.

Mentions:
The T‐cell immune responses were ascertained by the presence of IFN‐γ‐producing lymphocytes detected by ELISPOT assay using peptides EPFRDYVDRF from p24, DRVIEVVQGAYRAIR from gp41 and CTEMEKEGKISKIGP from RT as HIV‐1‐specific antigens. In a murine system, these peptides are multiple class I molecules, which can be presented to CTL. Figure 6 demonstrates that immunization with S. enteritidis E23/pcDNA‐TCI triggers CTL responses in comparison with control groups. These data relate to day 35 (day 7 after the second immunization), when the immune response was the strongest.

Bottom Line:
The gene coding for TCI protein was used to construct the eukaryotic expression plasmid pcDNA-TCI.Detectable antibodies were generated in 2 weeks after immunization and their level increased after second immunization.This study demonstrates that attenuated S. enteritidis E23 is an effective live vector for rectal delivery of the DNA vaccine pcDNA-TCI to generate humoral and T-cellular responses against HIV-1.